mmrecov(8)
mmrecov(8)
NAME
mmrecov - recover a NetWorker media index
SYNOPSIS
mmrecov [ -q | -v ] [ -N [ -F ] ]
DESCRIPTION
The mmrecov command is used in recovering from the loss of a NetWorker
server's critical files. mmrecov restores the media index and the
server's resource files. Typical events causing such disasters are
accidental removal of these files by a user or a disk crash on the Net-
Worker server itself. See nsr_crash(8) for a discussion of general
issues and procedures for NetWorker client and server crash recovery if
you are running NetWorker for UNIX.
mmrecov is used to recover the NetWorker server's media database and
resource files from the media (backup tapes or disks) when the media
database or resource files have been lost or damaged. Note that this
command overwrites the server's existing media index. The mmrecov com-
mand is not used to recover NetWorker clients' online indexes; you must
use the nsrck(8) command for this purpose.
The NetWorker system must be fully installed and correctly configured
prior to using this command. If any of the NetWorker software is lost,
re-install NetWorker from the distribution files before you run mmre-
cov. Use the same release of NetWorker, and install it in the same
location as it was before the software was lost.
The mmrecov program extracts the contents of a bootstrap save set,
which contains the media index and resource files. Once mmrecov is
done running, you shut the NetWorker server down, move the recovered
resource files into place, and restart the server. At this point, the
file indexes for the server and client may be restored by using nsrck.
When mmrecov is started, it will ask for the device from which the
bootstrap save set will be extracted. Next, it will ask for the boot-
strap save set identifier. This number is found in the fourth column
(labeled ssid) of the last line of the bootstrap information sheet
printed by savegrp and mminfo -B, an example of which is shown below:
Jun 17 22:21 1992 mars's NetWorker bootstrap information Page 1
date time level ssid file record volume
6/14/92 23:46:13 full 17826163 48 0 mars.1
6/15/92 22:45:15 9 17836325 87 0 mars.2
6/16/92 22:50:34 9 17846505 134 0 mars.2 mars.3
6/17/92 22:20:25 9 17851237 52 0 mars.3
In the example above, the ssid of the most recent bootstrap save set is
'17851237'. If you are cloning save sets, your bootstrap save set is
also cloned, and you need to use the second to last save set. See the
RECOVERING FROM CLONE MEDIA section for an example of boostrap informa-
tion with cloned save sets.
Next, mmrecov prompts for the file and record location of the bootstrap
save set. Both values may default to zero if they are not known.
Note, however, that specifying the correct file and record numbers will
allow NetWorker to more quickly locate the bootstrap save set. The
file and record locations are the fifth and sixth columns of the boot-
strap information sheet. In the example above, the values for the file
and record locations are 52 and 0, respectively. Finally, mmrecov will
prompt that the volume (`mars.3' in the example above) containing the
selected bootstrap save set be inserted into the specified device. The
ssid, file location, record location, and the physical volume must be
determined by the user from the printed sheet, since mmrecov has no way
of determining this information. On the other hand, if the volume con-
taining the bootstrap is not known, the -B option of scanner(8) can be
used to determine the file and record locations.
If the bootstrap save set spans more than one volume, multiple volume
names are printed. The order printed is the order required by mmrecov.
In the example above, the third save set produced on 6/16/92 begins on
volume 'mars.2' and spans to volume 'mars.3'. If a bootstrap save set
spans volumes, mmrecov will prompt for the name of the device where the
next volume has been loaded when an end-of-volume occurs. The volume
is then scanned, and the bootstrap save set extracted.
After the volume scan completes, mmrecov will complete. At this point,
if your original server resource files were lost, you must shut down
the NetWorker server, move the new resource files into place, and
restart the NetWorker server. Now the indexes can be recovered.
At the end of a bootstrap recovery, the contents of the media database
will be replaced by the data from the bootstrap saveset. If any volumes
in the recovered database was written to after the bootstrap saveset
was created, those savesets will not be in the media database and the
volume records will have incorrect tape position. Networker will use
the incorrect tape position to write new data, there by overwriting
data written since the bootstrap backup. In the case of file type or
advanced file type devices, recover space operation will delete all the
savesets which have been created since the time the bootstrap saveset
was created.
Consider the following situation. The networker databases needed to be
recovered today and the latest bootstrap saveset available is one day
old. After recovering the databases using this bootstrap saveset, the
media database will contain volumes and saveset records as of yester-
day. Any savesets created after the time the bootstrap saveset was cre-
ated do not exist in the media database, but they do exist in the phys-
ical medium. Networker will use the stale position information from
volume records for writing new data. This has the potential to over
write the saveset records that are missing from the media database.
To prevent this from happening, mark all volumes with the flag "scan"
using the option -N. This flag will instruct nsrmmd to find the real
end of tape. This will prevent data loss. To recover those savesets
created since the boostrap recovery, the administrator must scan in the
volumes. For file type or advanced file type devices, the recover space
operation will be suspended until the "scan" flag is turned off.
In order to recover the indexes for the server and client, you must run
nsrck -L7. This command will reconstruct complete indexes from the
save sets generated by the server's save schedule. Since the save sets
may be spread across multiple volumes, nwadmin(1) or nsrwatch(1) should
be run, and the volumes mounted as they are requested.
When nsrck completes, the message "completed recovery of index for
client '<client-name>'" is displayed. Once a NetWorker client's index
is recovered, that client can start recovering its files using recover.
Note that it is not necessary for the server's index to be restored
before the client indexes may be restored.
As stated earlier, the NetWorker resource files are saved as part of
the bootstrap save set. If your resource files were also deleted, you
may quickly replace them by copying or moving them from /nsr/res.R to
/nsr/res. Before restoring them to /nsr/res, the daemons must be shut
down (see nsr_shutdown(1)).
Sometimes it is neccessary to recover the NetWorker server onto a new
machine, for example, after a major hardware failure. When this
occurs, the NetWorker Licensing software will detect the move. Once
the NetWorker server has been moved to a new machine, it must be re-
registered with Customer Support within 15 days of the move, or the
server will disable itself. After disabling itself, you will only be
able to recover files; new backups cannot be performed until the server
is re-registered. Notifications will be sent by the NSR Registration
notification, warning of the need to re-register the product.
RECOVERING FROM CLONE MEDIA
If you are running mmrecov with clone media only, for example, at a
remote site, you will need to perform the recovery using a slightly
different method. When selecting the bootstrap identifier, make sure
that you are using the information associated with the cloned save set:
the last save set listed in the bootstrap output. Consider the follow-
ing list of save sets:
Jun 17 22:21 1996 mars's NetWorker bootstrap information Page 1
date time level ssid file record volume
6/14/96 23:46:13 full 17826163 48 0 mars.1
6/14/96 23:46:13 full 17826163 12 0 mars_c.1
6/15/96 22:45:15 9 17836325 87 0 mars.2
6/15/96 22:45:15 9 17836325 24 0 mars_c.2
6/17/96 22:20:25 9 17851237 52 0 mars.3
6/17/96 22:20:25 9 17851237 6 0 mars_c.3
In the example above, the ssid of the most recent bootstrap save set is
'17851237'. The cloned save set resides on mars_c.3 and the values for
the file and record locations are 6 and 0, respectively.
If you lost your resource files and need to use the ones restored from
mmrecov, the NetWorker server needs to be shut down so that you can
replace the installation resource files with your recovered ones.
Once the original resource files are in place, the NetWorker server
should be restarted. After it is restarted, you may recover the
indexes for the server and clients by issuing the nsrck -L7 command.
This command queries the media database for the index backups and
restores the indexes for the server and each client. If all clone vol-
umes needed are online when the index recovery proceeds, nsrck will
complete on its own.
If some of the volumes are not online, then nsrck will attempt to
recover the index from the original volume it was backed up to, and
therefore request the original media. In the example bootstrap output
above, mars_c.1 and mars_c.3 would both need to be online. If volume
mars_c.3 was the only volume online, then nsrck would also request
mars.1. To finish recovering the server's index in this case, you need
to perform the following steps:
1. Note what volumes are needed for recovery and delete them from
the media database.
NetWorker Management Console or nsrwatch(8) lists the volumes
needed for recovery in the Pending messages panel. Use NetWorker
Management Console or nsrmm(8) to delete the volumes from the
media database.
Given the scenario in the example above where only mars_c.3 was
mounted, we would have to delete mars.1 from the media database,
for example, nsrmm -d mars.1.
2. Restart the server to terminate the index recovery in progress.
Use nsr_shutdown(8) to bring the server down. Run nsrd(8) to
start the server again.
3. Recover the server's index by using nsrck -L7 servername.
When nsrck completes, the message "The index is now fully recovered"
appears.
OPTIONS
-q Quiet. Displays only error messages.
-v Verbose. Generates debugging information.
-N Needs to scan in the volumes. After recovering media database,
mark all volumes in the media database to indicate that they
need to be scanned in.
-F Set "scan" flag to file and advanced file type volumes only.
This option must be used with -N option. When specified, the
"scan" flag will not set for volumes that are on tape media.
FILES
/nsr If this was a symbolic link when the bootstrap save set was cre-
ated, it needs to be re-created manually prior to running mmre-
cov.
/nsr/res
This directory and its contents are saved as part of the boot-
strap save set. mmrecov restores this directory, and then
renames it to /nsr/res.R. The original directory is temporarily
renamed to /nsr/res.org while the bootstrap save set is being
recovered.
/nsr/mm/mmvolume
The NetWorker server's media index saved as part of the boot-
strap save set, and unconditionally recovered by mmrecov.
DIAGNOSTICS
Failed to set `scan' flag for the volume volumename
An error message to indicate that the "scan" flag was not set
for the specified volume. The actual error message will follow
this message.
BUGS
The name mmrecov is misleading; as a result, mmrecov is often used when
it is not needed. A name like
"recover_server_media_database_or_resource_files_when_missing" is more
descriptive. Note that any part of the bootstrap save set contents are
recoverable using normal recover procedures provided that the server's
on-line index, resource files, and media index are intact.
To recover files that are not in the on-line file index (for example,
files saved after the last run of savegrp), scanner must be used to
rebuild the media and on-line file indexes from the contents of the
volumes generated between the time of the last run of savegrp and the
loss of the original index.
SEE ALSO
mminfo(8), nsr_crash(8), nsr(8), nsrck(8), nsrd(8), nsr_client(5),
nsr_schedule(5), nsr_shutdown(8), recover(8), save(8), savefs(8),
savegrp(8), scanner(8), nsrindexasm(8), nsrmm(8), nsrmmdbasm(8),
nsrwatch(8), nsr_getdate(3)
NetWorker 7.6.2 Jul 14, 11 mmrecov(8)